Move chat to spectrum

Author: wooorm

contributing.md

@@ -34,14 +34,14 @@ help you faster.
 
 ## Questions
 
-Please chat and ask questions on Gitter!  Jump in there and lurk, talk to us,
+Please chat and ask questions on spectrum!  Jump in there and lurk, talk to us,
 and help others.
 
-*   [**unified**](https://gitter.im/unifiedjs/Lobby)
+*   [**unified**](https://spectrum.chat/unified/unified)
     — Topics relating to [**unified**][unified] in general
-*   [**syntax-tree**](https://gitter.im/syntax-tree/Lobby)
+*   [**syntax-tree**](https://spectrum.chat/unified/syntax-tree)
     — Topics relating to [**syntax-tree**][syntax-tree] and [**unist**][unist]
-*   [**remark**](https://gitter.im/remarkjs/Lobby)
+*   [**remark**](https://spectrum.chat/unified/remark)
     — Topics relating to the [**remark**][remark] ecosystem, markdown,
     and [**mdast**][mdast]
 

readme.md

@@ -1393,7 +1393,7 @@ By interacting with this repository, organisation, or community you agree to
 abide by its terms.
 
 Want to chat with the community and contributors?
-Join us in [Gitter][chat]!
+Join us in [spectrum][chat]!
 
 Have an idea for a cool new utility or tool?
 That’s great!
@@ -1440,7 +1440,7 @@ projects!
 
 [ideas]: https://github.com/syntax-tree/ideas
 
-[chat]: https://gitter.im/remarkjs/remark
+[chat]: https://spectrum.chat/unified/remark
 
 [releases]: https://github.com/syntax-tree/mdast/releases